Science Search

Science and Research Projects

Agroforestry systems for ammonia abatement - AC0201

Description

The overall aim of the project is to quantify the emission abatement of agricultural ammonia (NH3) that is achievable with a range of different on-farm woodland features at the UK scale, to provide tools to communicate optimised design strategies to users and to develop a methodology by which this abatement potential can be demonstrated to the UNECE. These aims will be achieved through process level work including experimental work in a wind tunnel facility and in the field, as well as numerical simulations. The project will build on the results of the recent DEFRA (MAFF) funded AMBER project (‘Ammonia Mitigation By Enhanced Recapture’; WA0719), which has demonstrated that a significant fraction of agricultural ammonia emissions could be avoided or recaptured through carefully designed agro-forestry systems. This project will further investigate and quantify the mitigation potential achievable through: (a) downwind shelterbelts for recapture, (b) silvopastoral systems and (c) wind breaks for sheltering emission sources, and propose optimised designs. The UK is committed to reducing ammonia emissions under the Gothenburg Protocol of the UNECE CLRTAP and the EC Emissions Ceilings Directive. Abatement through farm woodland features offers a complementary approach to reducing effective ammonia emission from agriculture, with the potential to lower overall costs of the emission reduction, while, at the same time, providing additional benefits for ecology, animal welfare, amenity and economic returns from timber production and grants. During the proposed project, operational tools will be developed to provide guidance to farmers, agencies and advisors to implement and maximise farm woodland abatement measures. These include user group meetings, a ‘Decision Support and Design Guide’ and a simple operational tool to estimate dispersion, recapture and impacts of ammonia at a given installation. In addition, the project will develop a coherent methodology to assess and demonstrate the benefits of ammonia mitigation by farm woodlands at the UK scale (including feasibility case studies) for the Convention and to promote this mitigation strategy in terms of ‘Best Available Techniques’.

Objective

The objectives of the proposed work are:(1) To assess the efficacy of farm woodland features for the recapture of agricultural ammonia emissions, through a combination of wind tunnel studies and numerical modelling, and to optimise their design.(2) To quantify ammonia recapture in silvopastoral systems through targeted field measurements.(3) To quantify the effect of upwind shelter for the reduction of ammonia emissions from farm sources through targeted wind tunnel measurements.(4) To provide accessible guidance and IT based design tools that can be used by farm managers to optimise farm woodland design and estimate effects in form of an updated “Farm Woodland Decision Support and Design Guide” and recapture parameterisations for a simple numerical dispersion screening tool.(5) To demonstrate the practical feasibility of implementing farm woodlands as ammonia abatement measures through case studies.(6) To quantify the potential of farm woodlands for ammonia mitigation at the UK scale.(7) To provide the vehicle to demonstrate farm woodland management as an abatement measure to the UNECE process, and to establish a framework of how spatial woodland management could be accredited as ammonia emission reduction.